1. Field of the Invention
This present invention generally relates to an air conditioning (AC) unit having an evaporator/blower housing adapted for mounting into the front or rear bulkhead of a bus or similar type vehicle for transporting a large number of occupants. More specifically, the invention relates to housings which are small, lightweight and easy to service and which allow evaporator/blower assemblies to be located distally from the compressor/condenser.
2. Description of the Related Art
Air conditioning units have been installed in various types of vehicles, with the design and operating parameters of the AC units adapted for installation in specific types of vehicles. Passenger buses presented particular problems due to the relatively large cooling load produced by the large number of passengers and the extensive window areas. Also, it is difficult to obtain effective air circulation through the large volume of internal space to be cooled. In prior art developments, passenger buses have been provided with AC units mounted on the roof or at other locations with the compressor assembly being driven from the engine which powers the bus. A condenser, condenser fan, evaporator and evaporator fan are associated with a compressor, expansion valve and other conventional components to provide a refrigeration system to supply conditioned air to the interior of the bus.
The following U.S. patents relate to the heating and cooling of a vehicle interior and the occupants therein: U.S. Pat. Nos. 4,201,064; 4,870,833; 5,428,967; 4,622,831; 4,926,655; 5,605,055; 4,727,728; 5,001,905; 5,609,037; 4,748,825; 5,184,474; 5,678,761; 4,787,210; 5,220,808; 6,295,826; and 6,494,052. These patents disclose various roof and rear mounted air conditioning and heating units for buses and other vehicles and are hereby expressly incorporated by reference in their entirety. However, the above listed patents do not disclose a self-contained AC unit which has an evaporator assembly separated and located distally from the compressor and condenser, allowing the evaporator assembly to take up much less space than a prior AC unit. As a result, the prior systems require a considerable amount of space, making them unsuitable for installation within the front or rear bulkhead of a bus or similar vehicle.
Further, one of the problems associated with installing evaporator components inside a vehicle has always been condensation. Water results from the hot humid interior air coming into contact with the cool evaporator surface, and drips onto the bottom of the unit housing where it must be drained away. Often the housing is made of multiple pieces of metal that are welded together. Constant exposure of the metal welds to the water causes corrosion and leakage into the interior of the bulkhead. Furthermore, operation of the AC unit while the bus is in motion can cause drainage problems for standard conventional drain pans, as the water sloshes laterally with the movement of the bus.
Accordingly, a need exists for a compact housing to contain an evaporator assembly that can be mounted in a front or rear bus bulkhead, remotely located from the associated compressor and condenser units. Also needed is a housing having a floor pan which is leak resistant and which facilitates drainage of condensate whether the vehicle is in motion or stationary in a non-level position, and which is shaped to allow for both ease of installation and access for service retrofit.